This invention relates to the field of airport ground traffic control systems and ore particularly to a system for determining aircraft position an airport surface and for providing warnings of potential collisions.
Unauthorized incursions f aircraft and ground vehicles onto runways and taxiways can often have catastrophic results. The number of aircraft accidents hat occur on the ground is nearly three times the number of aircraft accidents that occur in the air.
In poor visual conditions the problem becomes even worse since the ground controller is often reliant on non-visual information such as voice communications from the cockpit crew, reporting an aircraft""s current position on the airport surface, or on display information from a ground traffic control radar system. Unfortunately, due to their prohibitive cost, only some of the largest airports in the United States have ground traffic control radar systems to aid the controller. The remainder of U.S. airports depend solely on the visual observations of flight controllers and on position reports from pilots. Of the airports which have ground traffic control radar, some of these systems are modern systems such as the ASDE-3 systems. However, many existing ground traffic control radars are over twenty years old, are difficult to maintain, and ay provide inadequate information in poor weather because rain, snow, and fog tend to interfere with the radar signals. Thus in a large number of airports, during poor weather conditions, the flight controllers are often literally reduced to asking air crews xe2x80x9cwhere are you?xe2x80x9d to locate aircraft on the airport surface Fortunately, for any particular airport there are generally only a few taxiway/runway intersections that are critical intersections, i.e., those intersections that have a history of an excessive number of runway incursions.
What is needed therefore is a reliable yet low cost system that provides a warning of unauthorized runway incursions to the flight controllers. Ideally such a system will provide an audible warning to flight con rollers since the controllers are typically continually watching their air traffic control screens and may not notice a purely visual warning of a runway incursion. In addition, such a system should be free from the poor weather operational problems associated with conventional radar warning systems.
The present invention is a simple, low cost, but effective, runway incursion warning system for monitoring the critical runway/taxiway intersections of an airport and for communicating data indicative of a possible runway incursion to flight controllers or other airport personnel. The system uses off-the-shelf microwave radar motion detectors for detecting the approach of aircraft, ground vehicles or people. A microwave radar system has important advantage over a conventional radar system. Most notably, due to the comparatively short wavelengths of microwaves, such systems are to as affected by rain, snow, or fog, as are conventional radar systems.
In the system of the present invention, microwave radar transceivers or motion detectors are located at predetermined installation sites adjacent to selected runways and/or taxiways of the airport. The motion detectors include a transmitter unit and a receiver unit. The detectors operate by transmitting microwaves in a cone shaped dispersion pattern. When an aircraft or a ground vehicle enters the dispersion pattern some of the microwaves are reflected back to the motion detector and are detected by the receiver unit. Commonly available motion detectors may be configured t o detect motion in one direction only, thus the system of the p resent invention may be configured to selectively detect either incoming or outgoing traffic. The detectors may also be arrange in pairs to detect the direction of travel of an aircraft or vehicle.
In the system of the present invention, when the detectors detect the approach of an air raft or ground vehicle, a signal is transmitted to an annunciator located in the tower. The annunciator provides a verbal warning to tower personnel of a potential runway intrusion. Preferably, the annunciator is programable so that different voices will provide warnings depending upon, for example, where the runway intrusion is occurring. This feature is highly advantageous, in that by using a different voice to indicate a runway intrusion at each critical area, tower personnel will be able to immediately recognize where the intrusion has occurred without waiting to hear the complete warning. A further advantage of the present invention system is that it operates at low power and may utilize the existing cabling normally provided for runway lights. In one particularly preferred embodiment, the motion detector and associated hardware are integrated with a typical runway lamp. These and other features of the invention will become more apparent from the following detailed description of the invention, when taken in conjunction with the accompanying exemplary drawings.